首页
登录
职称英语
[img]2016m12s/ct_eyyjscz2015j_eyyjsccloze_0151_201611[/img] Diamond is the h
[img]2016m12s/ct_eyyjscz2015j_eyyjsccloze_0151_201611[/img] Diamond is the h
游客
2024-08-15
15
管理
问题
Diamond is the hardest naturally occurring substance known. It is the most popular gemstone and because of its extreme 【C1】______(hard), it is also used for various industrial purposes. Scientists are still 【C2】______(sure)of the exact process by which diamonds are naturally formed, but it is certain that both extreme heat and enormous pressure are needed. It is, therefore, likely that diamonds were formed far【C3】be______the Earth’s surface where these conditions exist. The first synthetic diamonds were successfully produced in the 1950s, but the best and largest stones are still those created by nature.
The word ’ diamond’ comes from the Greek ’ adamas’ , which means invincible, but the first definite reference to diamonds occurs in Roman literature of the first century A. D. The diamonds known to the Romans came from India, which was the only 【C4】______(supply)of the stones until the eighteenth century. In 1762, diamonds were discovered in Brazil, and then in 1866 in South Africa, the main source of diamonds in the world today.
The idea that men should give diamonds to the women they 【C5】______is quite new. It was invented in the last century by De Beers, the company that owns the South African diamond mines. The idea that ’diamonds are forever’ does not hold water either. Although diamonds are very hard, they can be【C6】dam______.
The largest of all known diamonds was the Cullinan. It was【C7】disc______in South Africa in 1905 and given to Edward VII, king of Great Britain. It was cut into smaller stones, the largest of which—and still the largest cut diamond in 【C8】______(exist)—is called the Star of Africa.
There have been a lot of diamond thefts in recent years, but scientists can now mark stones to show who own them. Usually this mark is 【C9】______(visible), so thieves can’t tell if a diamond is marked. 【C10】O______the people who know how to make the mark appear can tell whether a diamond is marked or not. [br] 【C2】
选项
答案
unsure
解析
(该句的意思是“科学家仍然不确定钻石自然成形的准确过程,但可以确定的是钻石的成形需要高温和高压”,由后文的转折词but可知,空格处应填人否定形式。)
转载请注明原文地址:https://tihaiku.com/zcyy/3720411.html
相关试题推荐
CVsfromAroundtheWorld[img]2016m12s/ct_eyyjsdz2015j_eyyj
CVsfromAroundtheWorld[img]2016m12s/ct_eyyjsdz2015j_eyyj
CVsfromAroundtheWorld[img]2016m12s/ct_eyyjsdz2015j_eyyj
[img]2016m12s/ct_eyyjsdz2016j_eyyjsdreadb_0169_201611[/img]ThelatestWorld
[img]2016m12s/ct_eyyjsdz2016j_eyyjsdreadb_0169_201611[/img]ThelatestWorld
Yourschoolwantstogive$500tooneofthetwocharitiesbelow.[img]2016m12s
Whichonecomesnext?[img]2016m12s/ct_eyyjsdz2015j_eyyjsdiq_0177_201611[/img]A
[img]2016m12s/ct_eyyjsdz2016j_eyyjsdd_0126_201611[/img]Thetermculturesho
[img]2016m12s/ct_eyyjsdz2016j_eyyjsdd_0126_201611[/img]Thetermculturesho
[img]2016m12s/ct_eyyjsdz2016j_eyyjsdd_0126_201611[/img]Thetermculturesho
随机试题
Theoceanbottom--aregionnearly2.5timesgreaterthanthetotallandarea
WhichofthefollowingsentencesdoesNOTincludeanadverbialclauseofconcess
下列各种分步法中,不必进行成本还原的有()。A.按实际成本综合结转法 B.平行
关于红细胞体积分布宽度,错误的描述是A.RDW可作为缺铁性贫血的筛选指标 B.
CO和NH在体内跨细胞膜转运属于A.单纯扩散 B.易化扩散 C.出胞或入胞
根据《建设工程施工合同(示范文本)》(GF-2013—0201)规定, 某工程
Thechangeinthatvillagewasmiraculou
B从每行或每列来看,都含有1个上下结构、1个左右结构、1个包围结构的汉字,由此问号处应选择一个上下结构的汉字,答案为B。
下列关于行政法律关系的产生、变更、消灭过程中的法律行为表述不正确的是()。
除另有规定外,浓缩丸全部溶散时限为A.1小时 B.2小时 C.0.5小时
最新回复
(
0
)